Various types of fluids are used in applications in upstream oil and gas industry, paint industry, polymer industry, pharmaceutical industry, etc. Understanding rheology of emulsions, slurries and suspensions is desirable in these applications. Typically, as two or more immiscible fluids flow through a pipeline, the mixing of the fluids varies at different locations within the pipeline due to varying shear rates. This flow phenomenon may result in formation of emulsions and suspensions that are substantially stable in shear environment but may separate as the effect of shear is reduced. It is desirable to determine rheological parameters such as viscosity, elasticity, and consistency for such fluids.
Conventional techniques for measuring the rheological properties of multi-phase fluids such as emulsion and slurries include mixing them in a separate pre-mixer. The emulsion formed after the mixing is subsequently transferred to a cup and bob assembly of a rheometer and the viscosities may be measured using the rheometer for different shear rates. However, mixing of the fluids using the conventional cup and bob systems is poor especially at low shear rates. Moreover, pre-mixed emulsions are substantially unstable.
Moreover, such systems use cup and bob with plain surfaces that do not provide enhanced mixing for multi-phase fluids. Therefore, such systems require substantially stable emulsions and slurries for rheology measurements. Moreover, as the pre-mixing is done in a mixer and the sample is subsequently transferred to rheometer the two mixed phases may have a propensity to separate during the rheological measurements. This may result in inaccurate measurements. Improved apparatus for measuring rheological parameters of multi-phase fluids and methods of their operation are desirable.